This item indicates the version of the AJCC API incorporated into the cancer registry software that created the record with TNM stage data in the 8^th^ and later versions. It should be recorded the first time the AJCC ID (including a value of 8) is determined. If the registry software incorporates the APCC API directly, the value is obtained from AJCC’s API. If the software instead incorporates AJCC’s Cancer Surveillance API, the value can be returned from there.

A valid value is required for all cases diagnosed 2018 or later that have values entered in the AJCC or related data items. Cases abstracted prior to implementation of this data item will be assigned a value of 08.XX.XX during the conversion to v21.

Over time the definitions and other content contained in the AJCC’s API may change. This item identifies the original API content used to code the TNM data.

Blank is allowable in the case that no AJCC or related input items are coded.